Paper Title
Flow Simulation of Shatt Al-Arab River by Hec-Ras 5.0.3

Shatt Al-Arab River is an important water body in the Basrah Governorate for human, agricultural and animal uses. The river is flow from Qurna district to Abu Flus district within Iraqi country, then the river becomes common borders with Iran until its outlet to the Arabian Gulf at Al-Faw district. The most important tributaries of the river within Iraqi country are the Tigris, Euphrates and Garmat Ali River. Therefore, this study aims to simulate the flow in Shatt Al-Arab River and parts of its tributaries using the latest version of Hec-Ras model (v5.0.3). The calibration and verification of model were showed that the final Manning’s roughness coefficients (n) of the main channels for Tigris, Euphrates, Shatt Al-Arab River, and Garmat Ali River were 0.028, 0.029, 0.033 and 0.033, respectively. Whereas, the Manning’s roughness coefficients (n) of the banks for the reaches river were 0.06. The Results were illustrated that a very good agreement between the simulated and measured stages, where the correlation coefficient (R2) was 0.88 (as average), so the maximum water velocity in the main channel was not exceeds 0.8 m/s and ranged up to this rate up to Qurna confluence and start to decrease behind it due to expanded the width of the river and increase the depths. Keywords - Hec-Ras, Shatt Al-Arab River, hydrodynamic, simulation